Re: [rtcweb] Draft proposal for updating Multiparty topologies in draft-ietf-rtcweb-rtp-usage

Magnus Westerlund <magnus.westerlund@ericsson.com> Wed, 16 April 2014 12:26 UTC

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Date: Wed, 16 Apr 2014 14:26:20 +0200
From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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To: Harald Alvestrand <harald@alvestrand.no>, <rtcweb@ietf.org>
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Subject: Re: [rtcweb] Draft proposal for updating Multiparty topologies in draft-ietf-rtcweb-rtp-usage
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On 2014-04-15 23:57, Harald Alvestrand wrote:
> On 04/15/2014 05:14 PM, Magnus Westerlund wrote:
>> Hi,
>>
>> I have considered these comments and are okay with modifying the
>> recommendation. I have modified the proposed text from Harald somewhat.
>> My proposal is the following:
>>
>>
>>     WebRTC implementations of RTP endpoints implemented according to this
>>     memo are expected to support all the topologies described in
>>     [I-D.ietf-avtcore-rtp-topologies-update] where the RTP endpoints send
>>     and receive unicast RTP packet streams to and from some peer device,
>>     provided that peer can participate in performing congestion control
>>     on the RTP packet streams.  The peer device could be another RTP
>>     endpoint, or it could be an RTP middlebox that redistributes the RTP
>>     packet streams to other RTP endpoints.  This limitation means that
>>     some of the RTP middlebox-based topologies are not suitable for use
>>     in the WebRTC environment.  Specifically:
>>
>>     o  Video switching MCUs (Topo-Video-switch-MCU) SHOULD NOT be used,
>>        since they make the use of RTCP for congestion control and quality
>>        of service reports problematic (see Section 3.8 of
>>        [I-D.ietf-avtcore-rtp-topologies-update]).
>>
>>     o  The Relay-Transport Translator (Topo-PtM-Trn-Translator) topology
>>        SHOULD NOT be used because its safe use requires a point to
>>        multipoint congestion control algorithm or RTP circuit breaker,
>>        which has not yet been standardised.
> 
> Grammar warning: The above can be parsed as either
> 
> (multipoint congestion control algorithm) or (RTP circuit breaker)
> 
> or
> 
> multipoint ((congestion control algorithm) or (RTP circuit breaker))
> 

It is the later that was intended. Because the topology requires
congestion control for multi endpoint.

Will reword.

Thanks

Magnus Westerlund

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